# CVE-2012-0391: Apache Struts 2 Improper Input Validation Vulnerability

- Exploited (CISA KEV): yes, added 2022-01-21
- Published: 2012-01-08
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 75.6% (100th percentile)
- CWE: CWE-20

The ExceptionDelegator component in Apache Struts before 2.2.3.1 interprets parameter values as OGNL expressions during certain exception handling for mismatched data types of properties, which allows remote attackers to execute arbitrary Java code via a crafted parameter.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Before feed history | — | — |
| AWS | Before feed history | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Before feed history | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

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